<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*去找list底下的第一个子节点;而且这个子节点得是一个li*/
        /*#wrap > .item:nth-child(1){
            background: pink;
        }*/


        /*去找list底下的第一个li*/
        /*永远以元素为中心*/
        #wrap > .item:nth-of-type(1){
            background: pink;
        }

       /*#wrap > span:nth-of-type(1){
            background: pink;
        }
        #wrap > div:nth-of-type(1){
            background: pink;
        }*/
    </style>
</head>
<body>
    <div id="wrap">
        <span class="item">span-1</span>
        <span class="item">span-2</span>
        <span class="item">span-3</span>
        <div class="item">div-0</div>
        <div class="item">div-1</div>
        <div class="item">div-2</div>
        <div class="item">div-3</div>
        <div class="item">div-4</div>
    </div>
</body>
</html>